A multi-resonator filter has a signal input terminal, a signal output terminal, and a plurality of resonator components. The plurality of resonator components include an input resonator component coupled to the signal input terminal, an output resonator component coupled to the signal output terminal, and at least one intermediate resonator component coupled between the input resonator component and the output resonator component. The input resonator component, output resonator component and the at least one intermediate resonator component are arranged in a sequence to define a signal path between the signal input terminal and the signal output terminal. The at least one intermediate resonator component includes at least one multiple resonator component, where each multiple resonator component includes a pair of individual resonators coupled in parallel where each individual resonator in a given pair of individual resonators has the same resonant frequency.

A micro-acoustic RF filter comprises first and second ports (101, 102). First and a second signal paths (120, 110) are coupled between the first and second ports and include a corresponding resonator (111, 121). The resonator of at least one of the signal paths is a micro-acoustic resonator. One of the signal paths includes also a phase shifter (232) serially connected with the resonator (111). The micro-acoustic RF filter achieves a broad passband determined by the resonance frequencies of the micro-acoustic resonators. The filter allows flexible adaption of the passband and stopband performance.

A filter with bulk acoustic wave devices is disclosed. The filter includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. The first bulk acoustic wave resonator includes a first raised frame structure. The first raised frame structure is a multi-layer raised frame structure. The second bulk acoustic wave resonator includes a second raised frame structure. The first raised frame structure has at least one more raised frame layer than the second raised frame structure.

A method and apparatus for modifying or controlling a resonator connected to a signal loop having an input, an output, and a closed loop frequency response. The signal loop has a primary resonator having a primary frequency response. There is at least one adjustable resonator having an adjustable frequency and a secondary Q-factor. An adjustable scaling block applies a gain factor. A controller is connected to the at least one adjustable resonator and the adjustable scaling block. The controller has instructions to adjust the closed loop frequency response toward a desired closed loop frequency response by controlling the adjustable frequency of the at least one adjustable resonator and the gain factor of the adjustable scaling block.

At least three acoustic filters circuits FC are arranged on a single chip CH. At least two of them are electrically connected already on the chip for multiplexing. This reduces space consumption and leads to smaller device size.

A communications module includes a module substrate composed of a plurality of insulating layers, a plurality of wiring layers, and a plurality of wiring vias; and a filter module disposed on the module substrate. At least one of the wiring layers overlaps the filter module in a thickness direction of the module substrate and is connected to a ground potential to function as a ground layer, and an entirety of at least one of the wiring layers and at least one of the wiring vias disposed in a first region in the thickness direction of the module substrate between the filter module and the ground layer are electrically connected to the filter module.

An RF filter (BPF) with an increased bandwidth is provided. The filter comprises a half-lattice topology and a phase shifter (PS) comprising inductively coupled inductance elements in a parallel branch parallel to a first segment (S1) of a signal path (SP) between a first port (P1) and a second port (P2) of the filter.

An acoustic wave device includes a piezoelectric substrate, a first band pass filter that is on the piezoelectric substrate and has a first pass band, and a second band pass filter that is on the piezoelectric substrate and has a second pass band at a higher frequency than the first pass band. The first and second band pass filters include resonators that include respective IDT electrodes. When a first total average metallization ratio is defined as an average of metallization ratios of all of the IDT electrodes included in the first filter and a second total average metallization ratio is defined as an average of metallization ratios of all of the IDT electrodes included in the second filter, the first total average metallization ratio is greater than the second total average metallization ratio.

An acoustic resonator assembly and a filter are disclosed. The acoustic resonator assembly includes at least two acoustic resonators vertically connected to each other. The acoustic resonator includes: an acoustic mirror, a bottom electrode layer, a piezoelectric layer, and a top electrode layer that are arranged on a substrate. An active area of the acoustic resonator is defined by an overlapping area of the acoustic mirror, the bottom electrode layer, the piezoelectric layer, and the top electrode layer. The acoustic resonator further includes a support layer arranged on the substrate or the piezoelectric layer on a periphery of a projection of the acoustic mirror on the substrate. The at least two acoustic resonators are vertically connected to each other through the support layer. The filter significantly reduces the volume and the area of a device, improves design freedom and reduces design difficulty, enhances product performance and greatly reduces costs.

An apparatus is disclosed for a reconfigurable filter. In example aspects, the apparatus includes a filter circuit that has a first filter port and a second filter port. The filter circuit includes a filter network, an acoustic resonator, and a switch circuit. The filter network includes one or more acoustic resonators coupled between the first filter port and the second filter port. The acoustic resonator is coupled to the filter network and coupled between the first filter port and the second filter port. The switch circuit is coupled between the acoustic resonator and the second filter port, and the switch circuit is configured to connect the acoustic resonator into a parallel acoustic resonator arrangement in a first state and connect the acoustic resonator into a serial acoustic resonator arrangement in a second state.